1. Field of the Invention
This invention relates to magnetic alloys for magnetic heads which are suitable for use particularly in high density magnetic recording.
2. Description of the Prior Art
In recent years, necessity for high density and wide frequency band recording in the magnetic recording art has increased. At present, high density recording and reproducing has been realized wherein magnetic materials having a high coercive force are used in magnetic recording media and the recording tracks are made narrow in width.
It is considered necessary that magnetic alloys whose saturation magnetic flux density is high be used as a magnetic material for magnetic heads used to record and reproduce information in magnetic recording media having high coercivity. Currently proposed magnetic heads make use of Fe-Si-Al alloys (Sendust alloys) or amorphous alloys in part or all of the head core. However, magnetic recording media now tend toward a higher coercivity than ever experienced. For instance, when the coercivity exceeds 2,000 Oe, it has been difficult to record and reproduce information of high quality when using magnetic heads made of Fe-Si-Al alloys or amorphous alloys.
On the other hand, a vertical magnetization recording system has been proposed and put into practice wherein information is recorded by magnetizing a recording layer along the thickness thereof, not along the horizontal direction of the medium. In order that the vertical magentization recording system is well performed, the magnetic head should have a thickness of not higher than 0.5 micrometers at the tip portion of the main magnetic pole. Accordingly, it is considered that the magnetic head should have a high saturation magnetic flux density even for recording on a magnetic recording medium with a relatively low coercivity. Known alloys for magnetic heads which have a saturation magnetic flux density higher than Fe-Si-Al alloys or amorphous alloys are those magnetic alloys having a major proportion of iron such as, for example, iron nitride, Fe-Si alloys and the like. These known magnetic alloys having a high saturation magnetic flux density also have a high coercive force and are thus unsatisfactory for use as a magnetic head. To avoid this, there have been proposed magnetic heads of a multi-layered structure wherein a magnetic material having a small coercive force such as Fe-Si-Al alloys or Permalloys is used as a layer film or films.
For example, if iron nitride, which is a magnetic alloy having a high saturation magnetic flux density, is used, its magnetic characteristics become poorer at a larger thickness. When a thickness of larger than 1 micrometer is necessary, a multi-layered film using other types of magnetic alloys or insulating materials should be used.
As will be apparent from the above, for the fabrication of a magnetic head having a high saturation magnetic flux density, magnetic alloys have to be used as a multi-layered structure. The multi-layered structure undesirably requires additional steps and/or costs, presenting the problem that reliability is difficult to maintain.